SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '037efc156763012a2688a0b77737d0ecfcabfbe71257dc349755159e7280d9ff' 
  AND token = 'eLrMM0VcyLkqfvukNSdKnXcj082FvMjKX31w77kKeH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}